[exim] Exim: "Too many connections" - clamav?

Hi,

a short while ago, there were many connections in state TIME_WAIT (as
netstat -t says) on my machine. Exim mainlog says "Too many connections"
on new SMTP connections.

The TIME_WAIT connections go to another machine where SpamAssassin and
ClamAV are running. I now disabled virus checking in the Exim config,
and the problem seems gone.

But there still are two questions:

- How can one explain that behaviour? I suppose that ClamAV wasn't fast
enough checking mail, so that Exim had to wait for ClamAV returning
it's result while new connections could not be handled. Is that true?
Does the MaxConnectionQueueLength ClamAV configuration option have to
do anything with this issue?

- What do I have to do to handle this better in future? I don't want to
leave ClamAV disabled all the time. Can I speed up the processing, or
can I use parallel processing?

The thread may be slightly off-topic, but I hope that there are many
people here using both Exim and ClamAV.

Thanks,
Peter